1991 Buick Lesabre not shifting out of second

I have a 1991 Buick Lesabre, transmission type is a 4T60. It will not go in to Drive. It goes into reverse and first and second gears just fine, but not drive.Therefore it will only go about 30 mph. Any ideas on what might be causing this and what we can check?

If the TV cable is not broken, then you have an internal transmission problem. A rebuild is needed.